Dosing
Masterbatch is a pigment or additive mixed at high concentration into a carrier polymer and formed into granulate. It is usually dosed into the base material at 1–4% to give color, UV resistance, antistatic or flame-retardant properties. Its greatest advantage over working with powder pigment is that it is clean, repeatable and dosable.
The carrier polymer must be compatible with the base material; an incompatible carrier causes color streaks, weak adhesion and loss of mechanical properties. The masterbatch manufacturer specifies the carrier and the recommended ratio; the ratio must be assessed together with the precision limit of the doser.
Masterbatch is the most expensive raw material component; overdosing is a direct cost. The excess added "to be on the safe side" with volumetric dosing comes back as a measurable saving when you move to a gravimetric system.
You start with the ratio the manufacturer recommends and verify it with color measurement (a spectrophotometer or a reference plaque). The consumption calculator gives the hourly, daily and monthly masterbatch requirement.